Troweling machine



April 1951 c. H. SPITLER z-rrm. 2,979,996

TROWELING MACHINE 4 Sheets-Sheet 1 Filed April 24, 1957 INVENTORS 64 {MH. SP/ n 6.2 uo/wv 0. 6/7 r61? By S WM April 18, 1961 c. H. SPITLER ETALTROWELING MACHINE 4 Sheets-Sheet 3 Filed April 24, 1957 IN VEN TORS a M#1 WWW m ad 4 Sheets-Sheet 4 TROWELING MACHINE wm QM R C. H. SPlTLERETAL llm m 3 I mm P! .m IVE? I w an \R mm IE? April 18, 1961 Filed April24, 1957 Ctr- in wwmmage m 5 mm W R Wm M E V/ 2 N2 WW 0 15 T A W M W BV. B

United States Patent TROWELING MACHINE Clem H. Spitler, Dayton, and JohnD. Gayer, Alliance, Ohio, assignors to Master Vibrator Company, Dayton,Ohio, a corporation of Ohio Filed Apr. 24, 1957, Ser. No. 654,836

8 Claims. (Cl. 9445) This invention relates to power operated concretetroweling machines, and more particularly to a generally neworganization in a machine as described offering improved efliciency,greater stability and compactness, and power and safety controls.

In machines of the class described, relatively stationary engine meansis supported upon a rotary series of troweling blades, which blades restupon the work surface of unset concrete, and, in the use of the machine,are ro tatively driven by the engine means to effect floating andfinishing operations upon the work surface. A handle is attached to theengine means and is held by the operator in order that the machine maybe guided over the work surface and in order that the engine-means maybe held from rotating with the troweling blades. Machines of the presentclass conventionally incorporate means for tilting the troweling bladesrelatively to the work surface and to the engine means in order that theaction of the blades upon the work surface may be varied, as fromfloating to finishing and vice versa.

The object of the invention is to simplify the construction as well asthe means and mode of operation of troweling machines, whereby suchmachines may not only be economically manufactured, but will be moreefficient and satisfactory in use, adaptable to a wide variety ofapplications, and be unlikely to get out of order.

A further object of the invention is to reduce the center of gravity ofthe machine by a general lowering of the parts thereof toward the worksurface, this being achieved by a structural concept in which the rotarymount for the troweling blades is constructed as a housing for the driveunit in the form of a gear train unit interconnecting the engine and theblade mount. 1

Another object of the invention is to obviate the need for manual bladeadjustment, there being introduced into the machine a principle of poweroperation remotely controlled by the operator from his position at thefree end of the handle.

A further object of the invention is to enable the troweling blades tobe adjusted in a tilting direction while the machine is continued inoperation, revolving the blades over the work surface.

Still another object of the invention is to provide for power tilting ofthe troweling blades in either direction without interrupting operationof the machine.

A still further object of the invention is to increase the driveefliciency from the engine to the blade mount through the use of helicalgears in the transmission and reduction mechanism instead of the beltdrive and worm gear combination heretofore known tobe used for thispurpose.

Still another object of the invention is to provide a safety control inthe machine which will prevent run away operation thereof, there beingprovided on the ban: dle an engine control means adapted to be receivedin the grasp of the operator on the handle and which when releasedenforces an idling of the engine.

A further object of the invention is to provide a troweling machinepossessing the advantageous structural features, the inherentmeritorious characteristics and the mode of operation herein mentioned.

With the above and other incidental objects in view as will more fullyappear in the specification, the invention intended to be protected byLetters Patent consists of the features of construction, the parts andcombinations thereof, and the mode of operation as hereinafter describedor illustrated in the accompanying drawings, or

their equivalents.

Referring to the accompanying drawing wherein is shown one but obviouslynot necessarily the only form of embodiment of the invention,

Fig. 1 is a view in perspective of a troweling machine in accordancewith an illustrated embodiment of the present invention;

Fig. 2 is a detail view in longitudinal section of the gear train unitof the machine;

Fig. 3 is a plan view of the top of the engine casting or mount, withthe engine removed and with a part of the casting broken away to show apawl and ratchet mechanism provided for tilting the troweling blades inresponse to a revolving motion thereof;

7 Fig. 4 is a view in cross section, taken substantially along the line44 of Fig. 3;

Fig. 5 is a view in cross section, taken substantially along the line5--5 of Fig. 3;

Fig. 6 is a view in cross section, with some parts omitted, showing theengine mount and its mutually supporting relation to the blade mount;

Fig. 7 is a detail view in side elevation of the handle, showing theconnections to the blade tilting mechanism from the relatively remotecontrol therefor on the handle;

Fig. 8 is a detail view in side elevation of engine idler control meansmounted on the carburetor of the engine; and

Fig. 9 is a view in longitudinal section through the engine control ofFig. 8.

Like parts are indicated by similar characters of reference throughoutthe several views.

Referring to the drawings, a troweling machine in accordance with theillustrated embodiment of the invention comprises, as shown in Fig. 1,engine means including a casting or mount 15. On top of the casting ormount 15 is a self contained internal combustion engine 16 supported onend upon the mount 15 in suchmanner that the driven rotary shaft 17thereof (see Figs. 2 and v6) projects axi-ally within the engine mount15 or more particularly into a longitudinal through opening 18 therein.The engine 16 is suitably bolted or otherwise secured to the mount 15 tocomprise therewith a unitary assembly. The mount 15 is formed on theperiphery thereof with a radially projecting portion 19 to which ispivotally attached a bracket 20 at one end of a tubular handle 21. Atthe other end of the handle 21 is a cross bar 22, provided for the graspof an operator, the handle being used to guide the troweling machineover the work and to be held to inhibit rotary motion of the enginemeans.

Also projecting radially from the engine mount 15 is a series of spokes23 terminating in, or secured to, at their outer ends a common ring 24which acts as a guard and defines the working area as traversedby arotary series of troweling blades 25. The latter rest upon the worksurface and support the machine thereon and are caused to revolve Withinthe work area by operation of the engine 16, as will hereinafter beseen.

The blades 25 are flat and generally rectangular in construction and aredisposed with their axes in respective planes tangential to a circleconcentric with the axis of engine shaft 17. Each has a longitudinallyextending rib 26 on its supper surface secured as by a Patented Apr. 18,1961 I web 27 to a longitudinally offset sleeve 28. The latter isrotatably mounted on a shaft 29 and has integrally formed therewith alaterally projecting arm 31. At its outer end, the latter is received ina cam slot 32 formed by segmental ribs on a ring 33 (see Fig. 6) mountedfor relative rotary motion in an external track 34 on the side of a bowlshaped housing 35 beneath the engine mount 15. Also on the exterior ofthe housing 35 is a series of tangential sockets 36, each receiving oneend of a respective shaft 29. The housing 35 thus carries the severaltro 'eling blades 25 for unison, bodily rotary motion, and the bladesare still further arranged for tilting motion about their respectiveshafts 29 in response to rotary motion of the ring 33 relatively to thehousing 35, this motion being resolved through the cam slot 32 and arm31 into a rocking motion of sleeve 28. As a result of such tiltingmotion, the leading edge of the blade is raised or lowered relatively tothe surface of the work with a corresponding change in the kind of workperformed, as is known in the troweling of unset concrete surfaces.

The open upper end of the bowl shaped housing 35 faces the under side ofthe engine mount 15, and the housing or blade mount is positionedconcentrically of opening 18 and engine shaft 17. The upper end of thelade mount is closed by a plate 37 fastened by studs 38 to the upperedge thereof. The closure plate 37 has a central opening therein withinwhich a bearing 39 is located for supporting a gear train unit 41.

The blade mount 35 receives and serves as an enclosure for a drive unit41 in the form of a gear train unit. The latter includes a housing 42 onthe upper end of which is a boss 43 received in the bearing 39 andabutting the underside of a flange 44 which is a part of the enginemount 15 and which defines the smallest diameter portion of the opening18 therein. A set of screw studs as pass through the flange 44- and intothe upper edge of the boss 43 whereby to hold the housing 42 of the geartrain unit 41 stationary along with the relatively stationary enginemount. 42 is closed by a plate 46 bolted thereto, the latter having acentral opening 47 receiving a bearing 48. Rotatable in the latter is acentrally projecting portion 49 of a gear 51. On the opposite side ofthe gear 51 is a recess 52 receiving one end of a pinion shaft 53. Onthe latter is a pinion 54 meshing with a gear 55 on another pinion shaft56 supported in the housing 4-2 outside the boss 43. Also secured to thepinion shaft 55 is another pinion 57 meshing with the gear 51. Installedin the central projecting portion 49 of the gear 51 is a plurality ofbolts 58 which extend out of the gear train unit by way of opening 47and are secured to the bottom portion of the blade mount or housing 35.The gear train unit thus affords a direct gear drive from the pinionshaft 53 to the gear 51 and thereby to the blade mount 35. The latter isaccordingly rotated with the gear train assembly within the gear trainunit 41. The connection provided by the bolts 58 is effective also toretain the blade mount in a concentric relatively fixed location withrespect to the engine mount and further suspends the blade mount fromthe engine mount in the event of the machine being lifted and carriedabout. In use, it is more accurate to describe the engine mount as beingsupported upon the blade mount, since the blades 25 in effect supportthe machine upon the work surface. In order to seal the area of contactbetween the blade mount and the engine mount, the closure plate 37 forthe blade mount is provided in the area surrounding bearing 39 with afelt seal ring insert in contact with a machined surface 61 on theunderside of the engine mount 15. The described one end of the pinionshaft 53 is rotatable in a bearing 115. The opposite ends of pinionshaft 56, in the housing 42, are rotatable in respective bearings 116and 117.

The lower end of the engine shaft 17 has a hearing The bottom of thehousing 4 62 installed therein receiving an upper end of the pinionshaft 53. A sleeve 63 is mounted on the shaft 53 between the bearing 62and the pinion 54. The sleeve 63 is keyed to the shaft 53 and at itsupper end is secured to a clutch shell 64. The shell 64 is a part of acentrifugal clutch assembly engageable to effect a driving connectionbetween'the shaft 17 and the pinion shaft 53. When the clutch isengaged, operation of the engine is accompanied by rotation of the blademount 35 and thereby by a sweeping action of the blades 25 over the worksurface. The speed of motion of the blades is a function of the speed ofoperation of the engine (reduced by the gearing in said gear train unit41) which in turn is regulated by a throttle control lever 60 mounted onthe handle 21 convenient to the hand of the operator and suitablyconnected, as by flexible cable, to the engine carbureter. When theclutch is disengaged the engine may idle or otherwise operate withouteffect upon the blade mount. In this regard, the use of a centrifugalclutch provides automatic actuation of the blade mount in response tothe speed of rotation of the engine shaft and may be constructed todisconnect the blade mount from the engine drive when the engine is atan idling speed. In the illustrated instance, the clutch mechanism shownin a part of a specific form of clutch wherein a centrifugally operatedmechanism is received within the shell 64 and rotatively driven by theshaft 17 in such manner that a predetermined speed of rotation of theshaft causes the centrifugal mechanism to establish a frictional drivingengagement with the shell 64, and, through the sleeve 63, to rotate thepinion shaft 53.

The ring 33, utilized to adjust the degree of inclination of the blades25 relatively to the work surface, is mounted in a track or groove 34 asdescribed, the track or groove being defined by an integral flange onthe side of the blade mount 35 and by an overhanging lip on the closureplate 37. The ring 33 is frictionally held in its mounting to rotatewith the blade mount 35 by means of a rubber 0 ring 33'. On the uppersurface of the ring 33 is an arcuate segment of a rack 65 projectinglaterally in overlying relation to a pant of the periphery of theclosure plate 37. Also in overlying relation to the closure plate 37,and vertically spaced therefrom is a bracket or mounting plate 66 madesecure against rotary motion relatively to the closure plate byinterconnecting studs or bolts 67, 68, and 69 (Fig. 5). The spaced apartWalls defined by the plates 37 and 66 provide a mounting for laterallyspaced apart stub shafts 71 and 72 suitably journaled at their ends inthe respective plates. On the stub shaft 71, in superposed relation toone another and effectively interconnected for unison rotation, are aratchet 73 and a pinion 74, the latter being in meshing engagement withthe upper part of a relatively elongated gear 75 the lower part of whichis in meshing engagement with the rack 65. The gear 75 is rotatablymounted on a stud 76 set in the plate 37. On the stub shaft 72, insuperposed, relation to one another and effectively interconnected likeelements 73 and '74, are a ratchet '77 and a gear 78, the latter inmeshing engagement with the rack 65. According to the construction andarrangement of parts, therefore, the ratchets 73 and 77 are in rotarydriving engagement with the rack 65 so that rotary movement imparted toeither of the ratchets is effective rotatively to adjust the ring 33 andthereby to tilt the blades 25 relatively to the work surface. Theratchets 73 and 77 are in vertically spaced apart or differenthorizontal planes.

The ratchet 73 is formed with a series of peripheral teeth '79 and aplanar or blank surface 81. Similarly, the ratchet 77 is formed withteeth 82 and a blank surface 33. The ratchets 73 and 77 are constructedidentically to one another and are mounted on their respective stubshafts in a like manner. The-machined peripheries thereof are adapted tomake selective cooperative engagement with respective pawls 84 and 85which are received in a recess 36 in the engine casting 15 and pivotallymounted therein on respective vertical studs 87 and 88. The pawls 84 and85 lie in. spaced apart horizontal planes corresponding to the planes ofrespective ratchets 73 and 77. An end 89 of the pawl 84 may beinterposed into the path of a tooth on the ratchet 73, as the ratchet iscarried or revolved about the axis of the casting 15 in response torotation of the blade mount 35. Similarly a corresponding end 91 on thepawl 85 may be interposed in the path of a tooth on the ratchet 77.

The end 89 of the pawl 84 is formed with a slot 92 and overlaps theadjoining end of the pawl 85 which is the end opposite to the describedend 91 thereof. The said opposite end of the pawl 85 is formed with anopening 93. The pawls 84 and 85 are interconnected by the turned overend 94 of a rod 95, such turned over end passing through the slot 92 andthe opening 93 so that a pu1ling or pushing motion exerted upon the rod95 is eifective to rock the pawls 84 and 85 about their respective studs87 and 88 and in respectively different directions. A spring pressedplunger 96 engages the pawl 84 and tends normally to hold the pawls inthe position illustrated wherein the resepctive ends 89 and 91 thereofare out of the paths of movement of the ratchets 73 and 77.

The opposite end of the rod 95 is connected to a lever 97 pivotallymounted at 98 to projection 19 of casting 15. Also connected to thelever 97 :is one end of a rod 102 which extends upward through thetubular handle 21 and is connected adjacent to'its opposite end to ananchor block 103 within the handle. A knob 104 is slidably mounted onthe handle exteriorly thereof and is con nected to the block 103 by ascrew fastener 105. Longitudinal sliding motion of the knob 104,relatively to the handle 21, accordingly effects an axial movement ofthe rod 102 and a rocking motion of the lever 97 with a resultinglongitudinal motion of the rod 95. Movement of the knob 104 forwardly ordownwardly of the handle 21 rocks the lever 97 in a counterclockwisedirection (Fig. 7) and eifects a relatively extending motion of the rod95. The results or effect upon the pawls 84 and 85 is to rock pawl 84 ina counterclockwise direction about'its stud 87 and to rock the pawl 85in a clockwise direction about its stud 88. A predetermined extent ofmovement of the mechanism in this direction serves to place the end 89of pawl 84 in the path of movement of the teeth 79 on ratchet '73. Theend 91 of pawl 85 is in this operation rocked a farther distance out ofcooperative relation with its ratchet 7 7 Return of the knob 104 to anormal or neutral position as illustrated restores the pawls 84 and 85to the normal position shown in Fig. 3 wherein both pawls areinelfective with respect to their associated ratchets. Continuedmovement of the knob beyond the neutral positon in an upward or rearwarddirection along the handle 21 effects a reverse movement of the partswith the result that the nose or end 91 on the pawl 85 is interposed inthe path of the teeth 82 on ratchet 77 while the pawl 84 continues to beineifective with respect to the ratchet 73.

The knob 104 is located adjacent adjacent to the grip or cros barportion 22 of the handle and so is readily accessible for manipulationby the operator. It serves as a remote control for the adjustment of thepawls 84 and 85 and thereby for selective adjustment of the blades 25 ineither direction.

The changing of the angle of adjustment of the troweling blades isaccordingly a power operation initiated and controlled by the operatorbut effected by power supplied from the engine. Thus, the ratchets 73and 77 are caused bodily to revolve with the blade mount 35 as thetroweling blades sweep over the work. The selective interpositioning ofone or another of the pawls '84 and 85 into the path of movement of anassociated ratchet results in engagement of the teeth of the ratchetwith an end of the pawl and a consequent imparting of a rotary impulseto the ratchet as it passes by the pawl. This increment of motion istransmitted through gearing to the rack 65 and results in acorresponding tilting adjustment of the troweling blades through acorresponding increment of movement and in a direction determined by thedirection of adjustment of the control knob 104. It may be seen,moreover, that the mechanism operates to adjust the blades in a seriesof steps, one for each revolution of the blade mount 35 as the ratchetteeth successively engage the pawl. The maximum permitted movement ofthe troweling blades in either direction is determined by the number ofteeth on the respective ratchets since the rotary movement of theratchets are discontinued as the planar surfaces 81 or 83 thereof reachcooperative relation with continue to be held in an actuated position.The work of adjusting the blades is carried out without interruption inthe operation of the machine and may bediscontinued at any desired pointby action of the operator in restoring the knob 104 to a neutralposition.

The machine incorporates a safety control designed to prevent a'run-awayoperation should the operator lose his grasp upon' the handle. Thiscontrol includes a lever 106 positioned to be received within the graspof the operator upon the cross bar 22. A cable 107 is connected at itsone end to the lever 106 and extends into and downwardly through thetubular handle 21. Near the lower end of the handle, the cable 107emerges therefrom and is extended for attachment at its opposite end toa stud 108 (Figs. 8-9) in one end of a lever 109 pivotally mountedintermediate its ends on a bracket 111. The latter is secured to thecarbureter assembly. The opposite end of the lever 109 is formed with aturned over ear 112 cugageable with a screw 113 attached to thebutterfly gate of the carbureter. A compression spring 114 is interposedbetween the pin 108 and a turned over portion of the bracket 111 in suchmanner as to cause the ear 112 on lever 109 to engage and hold the screw113 in a position in which the butterfly gate is closed or substantiallyclosed in such a way that the engine cannot operate at anything higherthan an idling speed. A retracting or pulling force exerted upon thecable 107 serves to rock the lever 109 in a clockwise direction from thefull line position shown in Fig. 8 to the dotted line position thereof,in the course of which motion the car 112 thereon releases the screw 113and permits free adjustment of the butterfly gate under control of thethrottle. Under the influence of the spring 114 the hand lever 10'6normally occupies a position as shown in Fig. 1 wherein it is indivergent relation to the cross bar 22 of the handle. When received inthe grasp of the operator, the lever 106 may be retracted and broughtback to a position substantially parallel to the cross bar. In somoving, the lever pulls upon the cable 107 and rocks the lever 109 in aclockwise direction with the result above described. Should the operatorrelease his grip upon the handle, while the machine is running, thecontrol of the described mechanism is restored immediately to the spring114'which rocks the lever 109 in a counterclockwise direction and,through its action upon the screw 113, reduce the speed of engineoperation to idling.

If found necessary or desirable, the ring '33 may be manually adjustedby grasping rods 115 and rotating the ring about the housing 35.

From the above description it will be apparent that there is thusprovided a device of the character described possessing the particularfeatures of advantage before enumerated as desirable, but whichobviously is susceptible of modification in its form, proportions,detail construction and arrangement of parts without departing from theprinciple involved or sacrificing any of its advantages.

While in order to comply with the statute the invention has beendescribed in lauguage more or less specific as to structural features,it is to be understood that the invention is not limited to the specificfeatures shown, but that the means: and construction herein disclosed 7comprise but one of several modes of putting the invention into, effect,and the invention is therefore claimed in any of its forms ormodifications within the legitimate and valid scope of the appendedclaims.

It will be seen from the structure heretofore described that the geartrain, its housing, the working blades and the blade mount are not inthe same plane but are in substantially the same plane since the geartrain and blade mount are substantially symmetrical about a horiontalplane and the blade assembly structure is just below said horizontalplane thereby producing a compact assembly in the vertical directionresulting in a substantial lowering of the center of gravity of themachine as compared to the prior art and in producing stability inoperation.

What is claimed is:

l. A power operated troweling machine, including drive means having arelatively stationary mount which in use occupies a position invertically spaced approximately parallel relation to a work surface, ahousing secured in immediately dependent relation to said mount, a geartrain unit within said housing operatively connected for drive by saiddrive means, a blade mount surrounding the periphery of said housing andoperatively connected to said gear train unit means for rotationthereby, troweling blades, means tiltably mounting said blades toperipheral portions of said blade mount in a substantially co-planarrelationship therewith for rotational movement therewith and tiltingmovement thereon and a ring frictionally engaging said blade mount and acam surface on said ring, means on said blades engaging said cam surfaceand means for retarding the rotation of said ring on said blade mount tocause tilting of said blades.

2. A troweling machine including a relatively stationary mount for drivemeans which in use occupies a position in vertically spacedapproximately parallel relation to a work surface, a gear train unitsupported in immediately dependent relation to said stationary mount,blade mount means surrounding the periphery of said gear train unit andpositioned substantially co-planar with said gear train unit andoperatively connected thereto for rotation thereby, troweling bladesconnected to said blade mount for rotation therewith, said trowelingblades being adapted to rest on the work surface and provide support forsaid troweling machine, said troweling blades being substantiallyco-planar with said blade mount and gear train unit whereby to effect alow center of gravity for said trowel ing machine.

3. A power operated troweling machine including a relatively stationarymount which in use occupies a position in vertically spacedsubstantially parallel relation to a work surface, a gear train unitsecured to and beneath said stationary mount, means housing said geartrain unit situated immediately below said stationary mount, a blademount surrounding said housing, means connecting said blade mount tosaid gear train unit for rotation thereby about said housing, blademeans pivotally connected to peripheral portions of said blade mount forrotation there with in a substantially common plane and tilting movementthereon, said blade means being adapted to rest on the work surface andsupport the troweling machine thereby, a ring type element frictionallyengaging the periphery of said blade mount and adjustably mounted onsaid blade mount substantially co-planar therewith, said ring typeelement having a cam surface operatively connected to said blade meansfor effecting tilt thereof on said blade mount corresponding toadjustment of said ring type element on said blade mount, meansselectively arresting rotation of the ring element in increments tocause relative movement between said ring type element and said blademount to change blade tilt adjustment.

4. A power operated troweling machine according to claim 3,characterized in that said means for adjusting said ring includes a gearrack on said ring, relatively rotatable pinions on said blade mount inmesh with said rack and for rotation therewith and rotatably adjustablerelative thereto, said ring having a cam surface, means interconnectingsaid cam surface and said blades for selective tilt of said blades inresponse to rotary adjustment of said ring relative said blade mount,and means selectively arresting rotation of the ring in increments tocause rel-ative rotational movement between said ring and said blademount to change blade tilt adjustment.

6. A power operated troweling machine, including a relatively stationarymount which in use occupies a position in vertically spacedapproximately parallel relation to a Work surface, said mount includinga central opening, a housing fixed to and depending from said mountsurrounding said opening having a gear train unit disposed thereinincluding means for. coupling'thereof to a drive means on saidstationary mount, a cup shaped blade mount surrounding said housing forrotation relative thereto, means on said gear train unit fixedlysecuring said blade mount to cause rotation, troweling blades pivotallymounted on the periphery of said blade mount adapted to rest on the worksurface to support the machine thereby, means defining a track aboutsaid blade mount, a ring engaging said track and frictionally engaging aperipheral portion of said blade mount for rotation with said blademount and means for rotatably adjusting said ring relative to said blademount, cam means on said ring, means connected to said blades andoperatively engaged with said oam means for tilting of the blades inresponse to relative adjustment of said ring on said blade mount.

7. A power operated troweling machine including a relatively stationaryengine mount, an engine in generally superposed relation to said mounthaving its drive shaft dependent therethrough, a blade mount positionedin immediately adjacent relation to the underside of said engine mount,a gear train housing disposed within the confines of said blade mountand secured to said engine mount against rotation and a gear train insaid housing operatively connecting said shaft and blade mount forrotation of said blade mount, troweling blades connected to said blademount for rotation therewith, said blades, blade mount and gear trainunit being substantially coplanar whereby to effect a lower center ofgravity for said machine.

8. A troweling machine including a relatively stationary engine mountfor drive means which in use occupies a position in vertically spacedapproximately parallel relation to a work surface, a gear train housingsupported in immediately dependent relation to said stationary mount andsecured to said stationary mount against rotation and a gear train insaid housing, blade mount means positioned substantially co-planar withand surrounding said gear train unit and operatively connected theretofor rotation thereby, troweling blades connected for rotation with saidblade mount and tiltably mounted thereon, said troweling blades beingadapted to rest on the Work surface and provide support for saidtroweling machine, said troweling blades being substantially co-p-lanarwith said blade mount and said gear train unit whereby to efiect a lowercenter of gravity for said troweling machine and blade tilting meanssupported on and substantially coplanar with said blade mountoperatively connected to said blades.

(Refer nces on following pag 10 References Cited in the file of thispatent FOREIGN PATENTS UNITED STATES PATENTS 698,767 France July 9, 19302,198,929 Whiteman Apr. 20, 1940 1131320 Austral! June 13, 19412,277,389 Conway Mar. 24, 1942 5 1,092,463 France 10, 1954 2,351,278Mathews June 13, 1944 OTHER REFERENCES 2'826971 Stevens 1958 EngineeringNews Record, May 19, 1955, p. 52.

2,826,972 Stevens Mar. 18, 1958

